﻿PROkSOBRANCHIATA. 



267 



except in the young state, and the nearly straight margins of the whorls instead 

 of the deeply furrowed margins which characterise that species. 



Size. — Axis, 4-12ths of an inch; diameter, l-8th of an inch. 



Locality. — Alum Bay (No. 29, Prestwich) ; rare. 



No. 189. Pleurotoma turpis. F. E. Edwards. Tab. XXVIII, fig. 2, a— c. 



P. testa elongutd, fusiformi, spiraiiter sulcata, in juventd costellatd : spird productd, 

 bitrientes totius testa in longitudine fere aquanti : anfractibus convexiusculis ; ad humeros 

 angulatis ; postice declivis, late cavatis, ad suturam crenulatis ; ultimo anfractu antice 

 sensim attenuato, in canali perbrevi ierminato ; sulcis spiralibus crebris, undulatis, 

 obscuris: aperturd oblongo-ovali ; labro arcuato, acuto ; sinu sub-triangulari, lato, medio- 

 criter prof undo, in margine collocato. 



Shell long, fusiform, spirally sulcated, and, in the young state, longitudinally 

 ribbed ; the spire much produced, forming nearly two third parts of the whole shell ; 

 whorls, seven or eight, slightly convex, angulated at the shoulders ; the posterior 

 margins slope gently backwards, are plicated round the sutural edge, and are deeply 

 channeled, imparting somewhat of a turreted character to the spire ; the body- whorl 

 tapers towards the front with so gradual a contraction as to be almost conical. In the 

 young shell the whorls present rather numerous, nearly straight ribs, which are lost 

 about the fourth or fifth whorl. The spiral furrows are shallow, close-set, slightly 

 undulating, obscure, and frequently decussated by the lines of growth. The aperture 

 is a lengthened, ovate form, and terminates in front in a short, wide, indistinct canal ; 

 the outer iip is arched, thin, sharp-edged, and smooth within ; and the sinus is three- 

 cornered in shape, not very deep, and wide, extending across the whole width of the 

 margin. 



This Pleurotoma presents a general resemblance to P. pyrgota; the latter species, 

 however, may be easily distinguished by the finely crenulated and more sharply 

 angulated shoulders of the whorls and the prominent, ridge-like line which borders 

 the suture. 



Size. — Axis, rather more than 1 inch ; diameter, 1 -3d of an inch. 

 Localities. — Clarendon, Southampton. 



No. 190. Pleurotoma subula. F. E. Edioards. 'Tab. XXIX, fig. 13, a, b. 



P. testa subulatd, spiraiiter obsolete lineatd, fere Icevi: spird elatd, sub-conicd : 

 anfractibus antice planiusculis, postice cavatis, ad suturam sub-incrassatis, marginatis ; 



